2,199 research outputs found
Smooth Solutions and Discrete Imaginary Mass of the Klein-Gordon Equation in the de Sitter Background
Using methods in the theory of semisimple Lie algebras, we can obtain all
smooth solutions of the Klein-Gordon equation on the 4-dimensional de Sitter
spacetime (dS^4). The mass of a Klein-Gordon scalar on dS^4 is related to an
eigenvalue of the Casimir operator of so(1,4). Thus it is discrete, or
quantized. Furthermore, the mass m of a Klein-Gordon scalar on dS^4 is
imaginary: m^2 being proportional to -N(N+3), with N >= 0 an integer.Comment: 23 pages, 4 figure
Semi-Parametric Maximum Likelihood Estimates for ROC Curves of Continuous-Scale Tests
In this paper, we propose a semi-parametric maximum likelihood estimate of an ROC curve that satisfies the property of invariance of the ROC curve. In our simulation studies, we demonstrate that the proposed estimator has the best performance among all the existing semi-parametric estimators considered here. Finally, we illustrate the application of the proposed estimator using a real data set
How to interpret a discovery or null result of the decay
The Majorana nature of massive neutrinos will be crucially probed in the
next-generation experiments of the neutrinoless double-beta ()
decay. The effective mass term of this process, , may
be contaminated by new physics. So how to interpret a discovery or null result
of the decay in the foreseeable future is highly nontrivial. In
this paper we introduce a novel three-dimensional description of , which allows us to see its sensitivity to the lightest
neutrino mass and two Majorana phases in a transparent way. We take a look at
to what extent the free parameters of can be well
constrained provided a signal of the decay is observed someday.
To fully explore lepton number violation, all the six effective Majorana mass
terms (for )
are calculated and their lower bounds are illustrated with the two-dimensional
contour figures. The effect of possible new physics on the decay
is also discussed in a model-independent way. We find that the result of
in the normal (or inverted) neutrino mass ordering
case modified by the new physics effect may somewhat mimic that in the inverted
(or normal) mass ordering case in the standard three-flavor scheme. Hence a
proper interpretation of a discovery or null result of the decay
may demand extra information from some other measurements.Comment: 13 pages, 6 figures, Figures and references update
Study on separation characteristics of two-phase flow in double helical separator
The helical separator plays an important role in improving the working efficiency of electric submersible pump. Separation efficiency of two-phase flow in double helical separator is studied by numerical simulation and theoretical calculation. It is found that the separation efficiency of helical separator increases with the increase of gas-liquid ratio and flow rate. At the same time, under the condition of constant helical number and gas-liquid ratio, the separation efficiency is best when the even difference of pitch is 10Â mm
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